which thresholds and laboratory assay best predict clinical outcome?
Department of Obstetrics and Gynaecology, University of Leicester, Leicester, UK. jjsw@lineone.net OBJECTIVE:To determine what threshold for proteinuria could best predict clinical outcome and whether this threshold could be applied universally to any biochemical assay. DESIGN: A prospective observational study of hypertensive pregnancies referred for further assessment after in a UK University hospital (n=197). Twenty-four hour urine protein was measured by two different assays [benzethonium chloride assay (BCA) and Bradford assay]. The differences between the two assays were calculated from Receiver Operating Characteristic (ROC) curves. Commonly used thresholds for defining preeclampsia (0.3 and 0.5 g/24 hours) were explored for both assays for the prediction of adverse clinical outcomes (severe hypertension, Birthweight<10th percentile, preterm delivery, and a composite biochemical/haematological derangement). RESULTS: The two assays are not equivalent. The prevalence of>300 mg/24